grab dict keys/values without iterating ?!

Tim Chase python.list at tim.thechases.com
Wed Dec 11 16:42:53 CET 2013


On 2013-12-11 09:46, Roy Smith wrote:
> The problem is, that doesn't make a whole lot of sense in Python.
> The cited implementation uses dicts at each level.  By the time
> you've done that, you might as well just throw all the data into
> one big dict and use the full search string as the key.  It would
> be a lot less code, and probably run faster.

You're right if the search term is a whole word, a single
dict-to-result works ideally. However, the OP asked about prefixes, so
the Python implementation I provided uses a dict-of-nested-dicts which
allows any arbitrary prefix, and then iterates over only the subset of
those that match.

If you need O(length-of-prefix) iteration of all results, I believe
that's the best way algorithm to use (implementation details could
differ for a more space-efficient structure perhaps; normalization
might help reduce dict-entries).

It's a specialized use-case, and doesn't have the O(1) lookup for
exact-matches (that's just a special case of prefix=word with no
sub-iteration, so would be O(length-of-search-word)).	

-tkc






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